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(11) | EP 0 085 206 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Separator for compressed air |
| (57) separator to separate water vapour and oil gas from a compressed air stream has a
casing (1) into which the air passes through an inlet pipe (2). The air flow is blocked
by a conical cover (4) in a sleeve (3) and this blocking of the flow causes condensation
of the water vapour and oil. The air then passes through a zig-zag tube (5) and impinges
on an L-shaped plate (6). This causes blocking of the air flow and additional condensation
occurs. Finally, the air passes into a tube (10) and from there to the convoluted
path (91) of a screw (9) in a part (72) of the outlet tube. This causes more condensation.
Thus there are three condensation steps so that virtually all the water vapour and
oil is removed from the compressed air. The condensed liquid collects at the bottom
of the casing and can be drained through drain (11). |
[0001] The present invention relates to a separator for.an air compressor which separates impurities such as water vapour or oil from an air stream.
[0002] Separators are now commonly installed into air compressor systems for filtering the air in the system so that it is free from impurities. There are three main types of separator:
(i) cooling type;
(ii) metal plate compartment type; and
(iii) net-grid type.
[0003] Each of these types of separator has problems or disadvantages. The cooling separator requires a large amount of energy to operate and is therefore unsuitable for commercial use. The metal plate separator has a low filtering efficiency and thus cannot be used in conjunction with industrial pneumatic tools. The net-grid separator has a poor filtering efficiency so that water vapour or oil gas remains in the air after it has passed through the separator. If the air is then passed to a spray gun, for example, water or oil still contained in the air may be discharged from the gun together with the desired material. Also, with the net-grid separator, oil, dirt or other foreign substances build u2 on the net-grid after prolonged use which reduces the efficiency of the circulation of the air and hence the efficiency of the performance of the separator.
[0004] . The present invention seeks to provide a separator which overcomes or at least ameliorates these problems. It utilises the condensation occurring when an air stream is deflected to remove water vapour and oil gas from compressed air.
[0005] An embodiment of the invention will now be described, by way of example, with reference.to the accompanying drawings, in which:
Figure 1 is an elevation view of a separator according to the present invention;
Figure 2 is a sectional view through the separator of Figure 1; and
Figure 3 is a detail of part of the separator of Figure 2.
[0006] Referring first to Figure 1, a separator according to the present invention has a body having a casing 1 with an elliproid cross section with an air intake pipe 2 on one side of the casing 1. The intake pipe 2 is L-shaped and passes into a cylindrical protective sleeve 3 and extends into the centre of the wider end of a conical cover 4. The cover 4 is located above one end of the intake pipe 2 inside the casing and the outer edge of the cover 4 is protected by the sleeve 3 which is a hermitically closed structure. The bottom of the sleeve 3 is connected to a zig-zag shaped tube 5, the convulated path of which causes further condensation. An L-shaped deflection plate 6 made, e.g., of iron is located opposite the outlet of the tube 5 which acts as an additional converger and separator of the water vapour and oil gas in the air. An air outlet pipe 7 is installed on another face of the casing 1 has a "T" shaped part inside the casing 1, the stem of the "T" extending out of the casing 1. A pressure meter 8 is installed at the end of the upper arm 71 of the cross piece of the "T" shaped air outlet pipe. The meter 8 is located outside the casing 1 so that the pressure, of the compressed air released from the air outlet pipe 7 can be monitored., A plug in the form of a screw rod 9 is provided in the lower arm 72 of the cross-piece of the outlet pipe 7 so that there is only a narrow convoluted passage formed by the slot 91 of the screw rod 9 between the upper arm 71 of the outlet pipe 7 and the end of the lower arm 72 (see Fig. 3). The end of the lower arm 72 is sealed except for a hole 73, and is located within a cylindrical pipe 10.
[0007] A draining control switch 11 for draining the liquid (waste liquid of mixed water and oil) accumulated inside of the casing is installed below the bottom edge of the casing 1. A connecting pipe 13 (Fig. 1) extends from the outer wall of the casing at the lower end thereof and is connected to a transparent high-pressure pipe 12 outside the casing 1. This pipe 12 permits observation of the volume of liquid of mixed water and oil accumulated in the air separator, so that it can be seen when it is necessary to drain the casing 1.
[0009] The separator is connected to an air compressor and to a pneumatic tool via the air intake pipe 2 and the air outlet pipe 7 respectively. The air compressor compresses the air (containing a large volume of aqueous vapour and oil gas) and discharges it into the casing 1 via the air intake pipe 2 where the air contacts the conical cover 4.
[0010] When air comes into contact with the cover 4, the air flow is blocked and, due to the compression force of the air and the hermatically closed structure of the sleeve 3, water vapour and oil are condensed. The condensed water vapour and oil form droplets on the walls of the cover 4, and flow along the walls of the tube 5 to the bottom of the casing 1. This process removes most of the water vapour and oil from the compressed air. The air is deflected by the cover 4 and passes out of the sleeve 3 into the-zig-zag shaped tube 5, On emerging from the tube 5, the air encounters the L-shaped plate 6 which again blocks the air flow, causing most of the residual water vapour and oil to be condensed. In this way, the amount of water vapour and oil in the air is reduced to a very small amount.
[0011] The compressed air with water vapour and oil gas removed by the cover 4, the zig-zag shaped tube 5 and the L-shaped plate 6, and escapes from the air outlet pipe 7 through the cylindrical pipe 10. However, when the air enters into the air outlet pipe 7 from the opening 73 and passes along the screw slot 91 of the screw rod 9 in the lower arm 72 of the pipe 7, it is again blocked and the (already small) volume of moisture and oil in the air is condensed into water and oil droplets which drop down to the bottom of the casing 1. Therefore, virtually all the . aqueous vapour and oil gas contained in the air will have been eliminated before it passes out of the outlet pipe 7. This elimination of oil and water vapour increases the useful life of the pneumatic tool, to which the pipe 7 is connected.
1. A separator for compressed air, to separate impurities from the air by condensation,
comprising
a first condensation part in the form of a hollow conically-converging member (4);
an inlet (2) for the compressed air having an outlet orifice directed towards the inner surface of the conically-converging member (4), such that, in use, air from the outlet orifice of the inlet (2) is directed onto the inner surface of the conically-converging member (4) and is deflected thereby;
an air-flow guide (3,5) extending around the first condensation part and at least a part of the inlet (2), at least part of the guide being in the form of a convoluted bore (5); and
a second condensation part (6) adjacent to but spaced from an end of the convoluted bore (5) such that, in use, compressed air passing through the convoluted bore (5) is = directed onto the second condensation part (6) and is deflected thereby.
2. A separator according to Claim 1, wherein the second condensation part (6) is an
angled plate, the end of the convoluted bore (5) being directed into the angle of
the plate.
3. A separator according to Claim 1, or Claim 2, having a third condensation part
comprising an outer member (7) and an inner member (9) forming therebetween a convoluted
passage (91) for air such that, in use, air from the second condensation part (6)
passes through the convoluted passage (91) and is deflected around that passage (91).
4. A separator according to Claim 3, wherein the outer member (7) of the third condensation
part is a tube (71,72) having a pressure meter (8) connected to one end (71), and
the inner member (9) is a plug having a screw thread on its outer surface, the inner
member being continued within the end (72) of the tube farthest from the pressure
meter (8), there being an outlet for condensed air at an intermediate point along
the tube (7).
5. A separator according to any one of Claims 1 to 4 having a casing (1) surrounding
the said condensation parts, the casing having an outlet (11) for draining liquid
condensed -in the casing (1).
6. A separator according to Claim 5, having means (12,13) for indicating the quantity
of liquid condensed in the casing.
7. A separator according to Claim 6, wherein the means (12,13) for indicating the
quantity of liquid in the casing is a tube (12).extending from the casing (1) and
being in ..,communication with the interior of the casing (1), at least a part of
the tube (12) being transparent.